1. Field of the Invention
The present invention relates to a keyboard and more particularly to a full keyboard, ten-key pad or similar manual inputting device.
2. Description of the Background Art
Keyboards in general are provided with various kinds of waterproof, dustproof structures, e.g. simple waterproof structures for daily use and sophisticated waterproof structures for medical and other professional use. For example, Japanese patent laid-open publication Nos. 10-222267 (Prior Art Document 1 hereinafter) and 9-305281 (Prior Art Document 2 hereinafter) each disclose a keyboard applicable to a personal computer and including an elastic waterproof cover configured to cover a support panel on which key switches are arranged. The waterproof cover mentioned above prevents oil mist and vapor from penetrating into switch devices included in the key switches. More specifically, the waterproof cover cooperates with a support base to fully cover the switch devices arranged on the support panel, which is positioned between the cover and the support base, thereby blocking dust and moisture from entering. When any one of keytops positioned above the elastic waterproof cover is depressed, the keytop presses the corresponding switch device via the cover.
Prior Art Documents 1 and 2 described above both have a problem that the waterproof mechanism is solid and therefore requires members exclusively prepared for the waterproof structure to be assembled, resulting in high production cost.